Solid Oak Software of Santa Barbara claims that the Green Dam package - which Beijing has declared must be installed on all PCs shipped in the People's Republic as part of its great battle against foreign filth - incorporates code from its own Cybersitter program.

The allegedly lifted code includes blacklists and update instructions, as well as a news update file dating back to 2004.

Solid Oak is seeking an injunction against the Chinese developer of Green Dam, Jinhui Computer System Engineering Inc, but its chances of gaining satisfaction must be reckoned to be fairly slim.

So, it's no surprise it is also seeking injunctions against US PC vendors who follow Beijing's directive that any machines they ship in China must carry the software.

"They are stealing proprietary copyrighted material from us, sending it over to the US and saying, 'We want this on all the computers you send us'," Solid Oak president Brian Milburn told Reuters. "Just because we are a small company doesn't make the theft of CyberSitter any less [wrong]."

Milburn told Reuters he had been tipped off via an anonymous email. "We found actual proprietary code areas within the Green Dam program itself which are incredibly suspicious because they use our proprietary encryption methods. There's a lot more to it than just a list of bad words."

Jinhui boss Bryan Zhang told a local paper: "That's impossible."

The code spat is the latest controversy to engulf Green Dam. The launch of the software last week was seen as a thinly-veiled attempt at further political censorship. Researchers quickly claimed to have found flaws which could allow the software to be used to create a giant botnet, sparking even quicker claims that this would be exactly what Beijing wants.

Other tests showed that the software was configured to block political material as well as smut, with Falun Gong and other political terms built into the software, along with mechanisms to stop Chinese using proxy servers to get round the country's Great Firewall. ®